Re: [PATCH RFC 54/77] ntb: Ensure number of MSIs on SNB is enough for the link interrupt

Alexander Gordeev
2013-10-05T21:43:04Z

On Wed, Oct 02, 2013 at 05:48:05PM -0700, Jon Mason wrote:
> On Wed, Oct 02, 2013 at 12:49:10PM +0200, Alexander Gordeev wrote:
> > Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
> > ---
> > drivers/ntb/ntb_hw.c | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> > index de2062c..eccd5e5 100644
> > --- a/drivers/ntb/ntb_hw.c
> > +++ b/drivers/ntb/ntb_hw.c
> > @@ -1066,7 +1066,7 @@ static int ntb_setup_msix(struct ntb_device *ndev)
> > /* On SNB, the link interrupt is always tied to 4th vector. If
> > * we can't get all 4, then we can't use MSI-X.
> > */
> > - if (ndev->hw_type != BWD_HW) {
> > + if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
>
> Nack, this check is unnecessary.

If SNB can do more than SNB_MSIX_CNT MSI-Xs then this check is needed
to enable less than maximum MSI-Xs in case the maximum was not allocated.
Otherwise SNB will fallback to single MSI instead of multiple MSI-Xs.

--
Regards,
Alexander Gordeev
agordeev@redhat.com